Road roller



Sept. 27, 19 56 A. 53. \NILLJAMSON ET AL ROAD ROLLER 3 Sheets-Sheet 1 Filed Sept 29, 1.958

mum m N H 4 r m M G B .P m 00H mu H w emu Mai/ 5 p 1960 A. o. WILLIAMSON ETAL 2,954,088

ROAD ROLLER Filed Sept. 29, 1958 3 Sheets-Sheet 2 INVENTORS 0 42cm: aMum/vsav BY 602220 0. GAR/s Marl hf Baa/v2 Arronqzy;

p 1959 A. o. WELLEAMSON ETAL 2,954,088

ROAD ROLLER Filed Sept. 29, 1958 3 Sheets-Sheet 3 FEEZ E INVENTORS 1422mm! QMaMnsou Gonna 0. 0442/5 Ma mv Beams EM M United States Patent ROAD ROLLER Archie 0. Williamson, Gordon 0. Garis, and Melvin H.

Boone, Minneapolis, Minn., assignors to Bros. Incorporated, Minneapolis, Minn., a corporation of Minnesota Filed Sept. '29, 1958, Ser. No. 764,005

1 Claim. (Cl. 180-20) This invention relates generally to compaction equipment and more particularly concerns pneumatic tired rollers such as used for compacting and maintaining road surfaces.

It is well known that in the building and maintaining of highways, airstrips and the like pneumatic tired rollers perform compaction and resurfacing operations in a highly satisfactory manner. While such rollers may be towed behind a draft implement, they may also be selfpropelled for ease of handling and greater maneuverability. It is with the latter type of roller that the present invention is concerned.

The self-propelled pneumatic tired roller is conventionally provided with a large ballast carrying body supported upon two longitudinally spaced sets of axially aligned pneumatically tired wheels, a motive engine for driving one set of wheels, and the other set of wheels being steerable from an operators platform on the body. For uniform transfer of the ballast and body weight to the tires, the wheels are disposed within downwardly opening recesses in the underside of the body and within the lateral limits of the body. The wheels in the two sets are generally alternately staggered with respect to each other so that the tires on the rear wheels will cover the spaces left between the front wheels on the surface being rolled. Accordingly, the wheels jointly cover the entire surface traveled and definedsubstantially by the lateral limits of the body.

The present invention is directed primarily to a selfpropelled roller of the relatively heavy fiat-top type such as approximates a weight of thirty tons or more when fully loaded with ballast. Normally a wet sand or aggregate ballast is used because of its economy availa bility and easeof handling. Because of the bulky nature of this type of ballast, the roller must of' necessity be of such a broad width as to render. it impossible for an operator sitting'in one position to achieve a vertical line 1 of sight with the outermost side faces, of both outside of .theroller over the area be side-by side with a minimum of overlapping or spacing therebetween. 'This can be,accom'plished only where'the operator has- .a'clear unobstructed view of the outer wheel of the roller'so that the roller may be operated with the tire tread of said wheel traveling along a predetermined line. Such line rolling is made difficult by the necessary size of the roller ballast carrying body. Further-more with the steerable set of compaction wheels lying within a somewhat confined recess on the underside of the body and with the entire set -of these wheels turning about a single vertical axis, the steering radius of a roller of this type can be very large. Also, the large :area of surface-tire cont act renders the steering of such rollers extremely diffioult. The turning of the roller around to permit the operator observation required is extremely diflicult, particularly Where the area is relatively narrow such as a roadway Patented Sept. 27, 1960 ice and may be impossible or against specifications under certain conditions. It is with these problems of heavy roller maneuverability that the present invention is concerned.

The principal object of the invention is to provide a novel construction for a self-propelled roller which will materially increase the accuracy and ease of steering of the roller.

Another and more specific object of the invention is to provide a novel steering mechanism and steering control arrangement for a self-propelled road roller which will enable the operator to maneuver the roller so as to completely and uniformly cover the surface to be rolled without the necessity of turning the roller around.

With these objects in view'the invention broadly comprises the providing of a road roller with a set of front wheels steerable about a single vertical axis, controls at each side of the roller connected to said front wheels for steering thereof about said axis, and said control connections being augmented by hydraulic power to effect said steering.

The above mentioned and still additional objects of the invention will be brought to light during the course of the following specification, reference being made to the accompanying drawings, in which:

Fig. 1 is a side elevation of the roller with the front portion of the body partially broken away to show certain elements of the steering mechanism.

Fig. 2 is a plan view of the roller with the engine partially broken away.

Fig. 3 is a front elevation of the roller again with certain front portions of the body broken away.

Referring now more particularly to the drawings reference numerals will be used to denote likeparts or structural features in the different views. The roller has a large box-like body, designated generally at 10. The body is rectangular in plan as shown in Fig. 2 and carries a substantially centrally mounted driving engine 11 which lies between and above ballast pockets 12.- The body is provided with a partially arched recess '14 at the rear end in which is disposed a set of pneumatically tired traction or drive wheels :15. The wheels 15 are axially aligned on a transverse axis and are driven by the en'- gine 11. In the present construction four equally spaced traction wheels 15 are used with the tires of the outermost wheels lying just within the lateral limits of the body 10. l

At the front end of the body 10 a partially arched recess 16 is provided, with the front end portion 17 of the body extending over the recess. A front wheel unit having a set of pneumatically tired front ground wheels 18 is disposed in this recess. 'The wheels 18 are transversely aligned on a common axle 19 and are staggered with respect to the rear wheels 15 to be in longitudinal alignment with the, spaces between such rear wheels. The front wheel ax-le is journaled in an inverted U-shaped bracket or bolster 20 which is pivoted as by pin 21 to a king pin ,22. King pin 22 has an integral shaft journaled for rotation on a vertical axis in the bearing 24 mounted on body portion 17. Accordingly, the bracket 20 and all of the wheels 18 are steerable as a unit about the vertical axis of the king pin 22.

A pair of transversely spaced operators stations are mounted on the body at the rear end thereof over the traction wheels 15. These stations are referred to as the left side and right side stations and are respectively generally designated at 30 and 31. Each station has a platform 32 upon. which there is mounted an operators seat 34, various controls 35 and a steering column 36 which journals a shaft 37 connected to steering wheel 38. The two shafts 3-7 are geared to a common cross shaft 39 so that both wheels will rotate the shaft in the same direction. Shaft 39 is connected to a longitudinally extending shaft 40 by means of intermeshing bevel gears disposed in gear box 41. The forward end of shaft 40 is connected as by a universal joint 42 to the rear end of shaft 44 which controls fore and aft swinging movement of arm 45 through mechanism in gear box 46. The arm 45 is pivotally connected to a bracket 47 mounted eccentrically on the king pin 22 by means of link unit 48. Accordingly, as either steering wheel is turned to the right or to the left, the motion will be transferred through shafts 37, 39 and 40, and gear box 41 to move the arm 45 forwardly or rearw-ardly about its pivot with link unit 48 acting upon the king pin 22 to turn the bolster and wheels 13 to the right or to the left, as the case may be.

A two-way hydraulic jack 50 has its rear end pivoted on a vertical axis to the body, as at 51, with the forward end of the extensible rod thereof pivotally connected to the bolster 20 as at 52. A fluid pump 54 is mounted adjacent the engine 11 and driven thereby. This pump is connected to a fluid reservoir 55 as by line 56. The pump is also connected by a pressure line 57 to a servocontrol valve 58 of the type commonly used in automotive steering and which is a part of the link unit 48. The valve 58 is a four-way control valve containing an internal piston operated by a ball at the end of arm 45- disposed in a socket in the valve. There are four lines connected to the valve. In addition to pressure line 57 leading from pump 54, a return line 59 connects the valve to reservoir 55, line 60 connects the valve to the anchored end of the jack 50, and line 61 connects the valve to the rod extending end of the cylinder.

The valve 58 is so operated by arm 45 that as the arm swings forwardly the valve will open line 61 to pressure line 57 causing retraction of the jack 50 to turn the bolster and the wheels carried thereby to the right about the axis of the king pin. At the same time the valve 58 opens line 60 to return line 59 for return of fluid already in the jack to the reservoir. Conversely, as the arm 45 is swung rearwardly it operates the valve to open line 60 to the pressure line 57 and to open line 61 to the return line 59 to cause extension of the jack and so to turn the bolster and wheels carried thereby to the left about the vertical turning axis of the bolster.

Thus the turning pressure exerted upon the bracket 47 by arm 45 through link unit 48 is augmented and in fact multiplied many times through means of hydraulic jack 50. As in automotive use the valve 58 has a servo action, resetting itself to give continuous resistance to further turning of the steering wheel. This, then, is a true power steering operation inasmuch as the turning is accomplished through the hydraulic system powered by the engine, while yet giving the operator the feel of the steering.

The two operators stations 30 and 31 are located on opposite sides of the body and just inside the lateral limits thereof enabling the operator to use the edge of the body as a line to roll by and to clearly observe the outside wheels on the roller and the adjacent ground surface. This allows the operator to completely cover the surface to be compacted without undue overlapping.

The operator has complete control of the roller from either side enabling him to accurately guide the roller along the intended path without the necessity of turning the roller around, an operation made extremely difficult due to the confined position of the front wheels in the recess 16. The roller "may, of course, be moved in either forward or reverse directions,

We have thus provided an improved construction for road rollers which economically and effectively carries out the aforementioned objectives. It is understood that suitable modifications may be made in the structure as disclosed, provided such modifications come within the spirit and scope of the appended claim. Having now therefore fully illustrated and described our invention, what we claim to be new. and desire to protect by Letters Patent is:

A self-propelled roller comprising a generally elongated box-shaped body having a set of rear traction wheels mounted in transverse axial alignment under one end of the body, an engine mounted on the body and having driving connection with the traction wheels, said body having a transverse recess under the end thereof opposite from the traction wheels, a front wheel unit including a set. of front wheels disposed in said recess in transverse axial alignment, the unit mounted on the body for turning thereof about a centrally located vertical axis, the wheels in the front set being in alternately staggered alignment with respect to the traction wheels with the outermost wheel on each side of the body extending approximately to the lateral limits thereof, a pair of control stations located one on each side of the body, each station having an operators seat and a steering mechanism located adjacent the lateral limits of the body whereby an operator at said station may visually observe the said outermost wheel at that side of the body, a transverse rotary shaft connecting the two steering mechanisms and rotatable thereby, a longitudinally extending oscillatable shaft having one end operatively connected to the transverse shaft to be oscillated thereby, mechanism connecting the other end of said longitudinal shaft to said front set of wheels for turning said wheels about said vertical axis as the said longitudinal shaft is rotated, the said connecting mechanism includes a gear box at the forward end of the longitudinal shaft having an arm swingable in fore and aft directions as the shaft is oscillated, a link unit connecting the arm to the front wheel unit, a hydraulically operated power jack connecting the front wheel unit to the body, and the said link unit including a valve for controlling how of hydraulic fluid to or from the jack.

References Cited in the file of this patent UNITED STATES PATENTS 

